Journal of Southwest Petroleum University(Science & Technology Edition) ›› 2025, Vol. 47 ›› Issue (1): 130-146.DOI: 10.11885/j.issn.1674-5086.2024.08.29.01

• A Special Issue on Deep Sea Oil and Gas Exploration and Development Geology • Previous Articles     Next Articles

Petroleum Geological Characteristics of Transformation-extensional Continental Margin Basins in East Africa

FAN Yuhai1,2,3, QU Hongjun4, ZHU Nan2   

  1. 1. Yulin University, Yulin, Shaanxi 719000, China;
    2. Aerial Survey and Remote Sensing Bureau of China Coal Geology Administration, Xi'an, Shaanxi 710199, China;
    3. Yulin Tongda Mingtai Geological Technology Co. Ltd., Yulin, Shaanxi 719000, China;
    4. Department of Geology, Northwest University, Xi'an, Shaanxi 710069, China
  • Received:2024-08-29 Published:2025-03-12

Abstract: In recent years, a series of large gas fields have been discovered in the deepwater areas of the Rovuma Basin and Tanzania Basin on the transform-extensional passive continental margin of East Africa, with recoverable reserves reaching 3.8$\times$10$^{12}$ m$^3$. However, the resource discovery rate in this region is merely 13.1%, indicating a vast potential for undiscovered resources. Based on the comprehensive research achievements of passive continental margin basins in East Africa, this paper summarizes the geological conditions such as source rocks, reservoirs, traps, and migration within the area, and explores the combination patterns of source-reservoir-cap rocks. The results reveal that: 1) The main source rocks in the transform-extensional passive continental margin basins of East Africa are mainly the lagoon facies and restricted marine shale or limestone of the Middle-Upper Jurassic-Cretaceous & the main reservoir rocks are the marine clastic rocks of the Middle-Upper Jurassic-Cretaceous-Neogene. 2) Hydrocarbons are charged into the reservoirs through "vertical charging" or "lateral charging" along faults, and "lateral charging" along unconformities or reservoirs; controlled by the complex tectonic evolution of East Africa, trap types dominated by structures and stratigraphic lithologies have formed. 3) The conditions for hydrocarbon accumulation are most favorable in the Rovuma and Tanzania basins, and the favorable exploration horizons are the sandstone reservoirs of the Cretaceous-Neogene. The Triassic Calub Formation sandstone in the Somali Basin holds promising exploration prospects. With the advancement of exploration degrees and technical levels, significant breakthroughs are expected in the oil and gas exploration of other basins.

Key words: transformation-extensional basin, deepwater, petroleum geology characteristics, exploration potential, continental margin basin of East Africa

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